M3 Grade Separated Diamond Interchange

The Navan Road Interchange was part of an overall civil & structural scheme that included 2,500 residential units, a new Railway Station with Park & Ride, Commercial Units, Infrastructural Works and a new Bridge across the M3. The design includes bus lanes and stops on each off ramp together with off road cycle and footpath facilities which integrate with the existing bus and cycle network.

The bulk of the works involved the construction of a 60.0m span bridge with two lane on and off ramps, the provision of two MOVA signalised junctions, the construction of a railway station car park, public lighting, utilities, landscaping and other associated civil engineering works. The construction of the bridge over live traffic and adjacent to the 9C Trunk Sewer along the N3 posed significant engineering challenges for the designers and put a significant level of restrictions on the contractor. Extensive engineering input was made into Traffic Management Planning for the construction of the scheme which was carried out over a live dual carriageway carrying over 25,000 vehicles per day.

The bridge design utilised precast concrete beams and foundations constructed of steel H piles rock-socketed in the abutments with raft foundations for the central pier. The design of the scheme took approximately six months to complete. OCSC provided detailed design, PSDP, contract administration and site supervision services on the project for our client.